jaymancds
Member
Al, this is mathematically true, but similar to your "theory" on calculating stagger, they will not be the same in practice. They will act differently as they are different, and the torque associated with them will be different.
Small gear vs. regular gear
- Thread starter TDFracing
- Start date
XXX#40
2A supporter
Put all those gears on a bicycle, when you become the torque arm you'll understand.
alvin l nunley
Site Supporter
I believe the torque stays exactly the same, but for reasons unknown to me right now, the actual performance on the track has some variance. What the reasons are for this performance variance are unknown to me at this time, I only have theories. Even at that, my theories are real sketchy.
alvin l nunley
Site Supporter
It sounds like you may have some experience with this,Would you caare to tell us about your experience?
jaymancds
Member
Yes they are sketchy. Your theory is wrong. The useable torque curves are different between each of those combinations.
I like this answer,,, I'm right your wrong,,,,but I have nothing to back it but my opinion and the wide open phrase of "usable torque curve" can't prove anything but I'm right by golly
jaymancds
Member
It is actually basic engineering. Different gears, even with the same ratio, will behave differently. The reason, and I quote, "Different things doing the same job, will react differently, even with the same result". I can't give you a book, I can only give what I have been taught. Unfortunately I don't have access to the data anymore.I like this answer,,, I'm right your wrong,,,,but I have nothing to back it but my opinion and the wide open phrase of "usable torque curve" can't prove anything but I'm right by golly
paulkish
old fart
Its not unknown to you.
You either don't have the ability to accept reports by others or you refuse to
.
Go save but " unfortunately"
XXX#40
2A supporter
One set helps you get there quicker
One set helps you stay there easier.
In BMX we could shorten or lengthen the cranks, which also effected the way the ratio was used.
it wasn't to long ago that the subject of "a ratio is a ratio" aka "small driver vs large driver" was debated for pages. I did a search but came up with a few posts listed below
I supplied some actual calculated engineering numbers that described the action of the chain as it wrapped around various drivers (chordal geometry). I know Paul Kish was vary involved / spearheaded (?) that discussion. And if Paul was there, I bet Al was there. The calculations supported the claim that different size drivers affect the way power is transmitted..
Here are some links to this old debate:
(do search for "ratio" and user "PaulKish")
Chain engineering link
proof a ratio is not a ratio link
Gear ratio selection link
That aught to keep yous busy for a while. Report back in the morning
I supplied some actual calculated engineering numbers that described the action of the chain as it wrapped around various drivers (chordal geometry). I know Paul Kish was vary involved / spearheaded (?) that discussion. And if Paul was there, I bet Al was there. The calculations supported the claim that different size drivers affect the way power is transmitted..
Here are some links to this old debate:
(do search for "ratio" and user "PaulKish")
Chain engineering link
proof a ratio is not a ratio link
Gear ratio selection link
That aught to keep yous busy for a while. Report back in the morning
Here is an important one you missed.it wasn't to long ago that the subject of "a ratio is a ratio" aka "small driver vs large driver" was debated for pages. I did a search but came up with a few posts listed below
I supplied some actual calculated engineering numbers that described the action of the chain as it wrapped around various drivers (chordal geometry). I know Paul Kish was vary involved / spearheaded (?) that discussion. And if Paul was there, I bet Al was there. The calculations supported the claim that different size drivers affect the way power is transmitted..
Here are some links to this old debate:
(do search for "ratio" and user "PaulKish")
Chain engineering link
proof a ratio is not a ratio link
Gear ratio selection link
That aught to keep yous busy for a while. Report back in the morning
Probably more applicable than a couple of the others.
Ymmv.
https://4cycle.com/karting/threads/rotational-torque.110040/
Here is another applicable link.
https://4cycle.com/karting/threads/horsepower-what-is-it.114778/
Caution, if you have no interest in doing the math yourself, expect to get exactly what you put in, out of the exercise.
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OVALTECH1
Site Supporter
I myself through years of big car racing relate what I need to ring and pinion sizing of a Ford 9”. I already know my rpm swing of my engine so I just gear accordingly. If it’s a tight track that works the kart and engine harder and the drops are big I know I need it to recover quick so you would use something like a 4:56 in car world. Now that ratio can be had clean up to a 16 or bigger driver but in a 9” it’s tiny pinion so I’ll use my 11 or 12 driver. If it’s a momentum track where you keep the engine buzzing along with very little off pedal time much like racing along at highway speeds you would have a 3:00 gear set in and you would be fine. The 3:00 uses a big ol pinion gear so your 14 or 15 would be the go to. Just how I always related it. Like it was said 100 times before a ratio is a ratio .... YES..... mathematically but at certain times one particular ratio works a lot better than the others of the same that number. That driver size goes a long way in helping what you need done be it one way or the other. Just my 2 cents.... fire away !
When we are limited by design, the effects of ratio is fairly constant. However, gear bound is still a possibility.
Use of a quick change with different initial ratio can change the output range.
GM's crate engines has taught me that gear bound can be overcome by carb choices, and thoughts on how to use the available power.
Dyno sheets only tell the story if used exactly as described by the torque curve.
There are ways to use this otherwise with a distinct advantage.
Follow the leader, or monkey see, monkey do, nets the same result, following the same guy, especially since you have no idea why what you are doing works at all.
Karting alone does not have these problems.
Just more options to overcome the same issues.
Use of a quick change with different initial ratio can change the output range.
GM's crate engines has taught me that gear bound can be overcome by carb choices, and thoughts on how to use the available power.
Dyno sheets only tell the story if used exactly as described by the torque curve.
There are ways to use this otherwise with a distinct advantage.
Follow the leader, or monkey see, monkey do, nets the same result, following the same guy, especially since you have no idea why what you are doing works at all.
Karting alone does not have these problems.
Just more options to overcome the same issues.
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SoCo Tire Treatments
Moderator
Whats that suppose to be? Has no meaning what so ever to me saying you dont use the same ratio when using the mini gears.
If you had any experience and knowledge with the mini gear set up ( i have quite a bit and have been using them for several months now ), you would know this.
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steve baker
Moderator
The angle of chain wrap around the gears as this relates to rotating dynamic friction plays into the track performance also.
This could easily be tested and analyzed on an accurate dyno using the various gear tooth sizes while using the same gear ratio's during each test.
Steve
This could easily be tested and analyzed on an accurate dyno using the various gear tooth sizes while using the same gear ratio's during each test.
Steve
So, oiling the chain will produce the same effects as changing from big gear to mini gear or vice versa?
steve baker
Moderator
That's what accurate testing can validate!
paulkish
old fart
alvin l nunley said:
"10/40 = 4-1
11/44 = 4-1
12/48 = 4-1
13/52 = 4-1
any questions?? //"
Not arguing at all.
Al, did you ever do your torque test by unwinding an equal weight hung by a string wrapped around a RR tire, then timing it to get numbers for a calculation:
On 4 different equal gear ratios.
I'm thinking if you did and got 4 equal torque calculations it would be a good argument for each working the same no matter what the physical difference.
I hope you did and can remember back at the results correctly.
I hope I remembered your how to find torque idea correctly?
I too know how easy it is to forget stuff. ...
If anyone understands what I'm asking and wants to try it, I think it would be very telling.
Maybe even proving Al correct no matter what your racing experience.
If different size gear combinations test the same it will be hard evidence.
You might even use the same amount of chain each test to eliminate chain and put your results more towards different gears only?
If 4 different gear sets give an equal timing number when the weight falls turning the tire when unwound an equal distance, I think then we must look for other reasons for a performance difference. and.... ... ???????????
edit: I'm now thinking the weight would have to fall long enough to allow it to get up to maximum falling speed for the test to be valid.
I'm also now thinking if after falling long enough the rate at which the weight gets to maximum falling speed would be different and that might be where the true performance difference lies.
Maybe when tested you'll get a different torque curve for each different rate of acceleration of the falling weight.
And maybe using different ratios is about matching up the gear's torque curve to your racing needs?
...yeah way way out in the left field now. ...
"10/40 = 4-1
11/44 = 4-1
12/48 = 4-1
13/52 = 4-1
any questions?? //"
Not arguing at all.
Al, did you ever do your torque test by unwinding an equal weight hung by a string wrapped around a RR tire, then timing it to get numbers for a calculation:
On 4 different equal gear ratios.
I'm thinking if you did and got 4 equal torque calculations it would be a good argument for each working the same no matter what the physical difference.
I hope you did and can remember back at the results correctly.
I hope I remembered your how to find torque idea correctly?
I too know how easy it is to forget stuff. ...
If anyone understands what I'm asking and wants to try it, I think it would be very telling.
Maybe even proving Al correct no matter what your racing experience.
If different size gear combinations test the same it will be hard evidence.
You might even use the same amount of chain each test to eliminate chain and put your results more towards different gears only?
If 4 different gear sets give an equal timing number when the weight falls turning the tire when unwound an equal distance, I think then we must look for other reasons for a performance difference. and.... ... ???????????
edit: I'm now thinking the weight would have to fall long enough to allow it to get up to maximum falling speed for the test to be valid.
I'm also now thinking if after falling long enough the rate at which the weight gets to maximum falling speed would be different and that might be where the true performance difference lies.
Maybe when tested you'll get a different torque curve for each different rate of acceleration of the falling weight.
And maybe using different ratios is about matching up the gear's torque curve to your racing needs?
...yeah way way out in the left field now. ...
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